Hair forms from a complex process involving stem cells, keratinization, and the hair follicle.
Here's a breakdown:
- Stem Cell Division: The process begins at the base of the hair follicle, where stem cells rapidly divide and differentiate into specialized cells called keratinocytes.
- Keratinization: These keratinocytes migrate upward, flattening and dying as they move. This process, called keratinization, produces keratinized cells that form the structural basis of hair.
- Hair Follicle Growth: The hair follicle is a tube-like structure that encloses the hair shaft as it grows. It provides nourishment and support for the growing hair.
- Hair Shaft Formation: The keratinized cells form a rod of tissue within the hair follicle. As more cells are produced, the rod pushes upwards, ultimately emerging from the skin's surface as the hair shaft.
- Hair Color and Texture: The color of hair is determined by the type and amount of melanin produced by melanocytes located in the hair bulb. The texture of hair is influenced by the shape and thickness of the hair shaft.
Hair growth is a cyclical process, with phases of active growth, resting, and shedding.
In addition to its role in hair growth, the hair follicle also plays a crucial role in:
- Skin repair: After an injury or wound, hair follicles help repair damaged skin.
- New skin formation: Hair follicles contribute to the formation of new skin cells.
